The invention relates to a coupling device according to the preamble of claim 1, which is used for coupling containers to each other, and particularly for coupling containers used in cargo ships to each other. In addition to sea transport, containers are also used for land transport.
Conventionally when aboard ships, stacks formed by containers are able to tilt sideways, depending on the degree of the list of the ship. This means that at least two corners i.e. those of one or the other side of the container are under pressure caused by the mass of containers above them.
On the other hand, when lifting containers, they are lifted so that all four corners are lifted up at the same time. For this reason, it is possible to distinguish clearly when the coupling devices of the containers have to be brought to a locking mode or an unlocking mode. In known arrangements, a vertical force, i.e. lifting force, is converted in the coupling device into a lateral (horizontal) force which compels the container being lifted, the upper and the lower one, to move sideways in relation to each other.